difference between GPS on a smartphone and a stand alone unit?September 4, 2012 6:39 AMSubscribe

What is the difference between GPS on your phone and GPS on a stand alone unit?

I inheirited a stand-alone GPS unit (pretty basic) from a friend and I'm curious about the difference between this (which has a battery life that is much longer, and I could definetly see a reason for using it), and a standard smartphone with GPS. For instance, often I can't use the GPS on my smartphone without data turned on as well. Is this so the maps can be downloaded? What would I need to do to be able to have my smartphone's GPS working when I am abroad without data roaming?

The GPS on my smartphone (iPhone if it matters) doesn't talk to me, so I need to keep looking at it to see which way to go.posted by lyssabee at 6:51 AM on September 4, 2012

The biggest difference, for me, is that I can use my stand alone GPS totally anonymously in that I am certain it is not reporting my location back to anyplace or, if somehow it was, that location isn't linked to any of my other personal information like my name, friends' names or anything else. Stand alone GPSes for cars often require a clear line of sight to the sky and won't work in buildings or parking garages or even other parts of the car that aren't near the window. Which smartphone do you have? I think the Maps applications work somewhat differently depending on whether you have an older iphone, a newer iphone or an Android phone.posted by jessamyn at 6:51 AM on September 4, 2012 [1 favorite]

Sorry - when i say GPS - i mean one of the handheld ones you can walk around with or go hiking with. I don't mean a Garmin GPS unit for driving in your car.posted by waylaid at 6:55 AM on September 4, 2012

For instance, often I can't use the GPS on my smartphone without data turned on as well. Is this so the maps can be downloaded?

The Google Maps app doesn't have downloaded maps at all, it's basically like an app frontend to the Google Maps website. So it won't really work at all if you don't have data. Not sure about the other popular smartphone GPS apps but that's the main one I'm familiar with. To have the full GPS maps locally on the device it requires several gigabytes of data, and the companies that license the maps charge significantly more for it.

What would I need to do to be able to have my smartphone's GPS working when I am abroad without data roaming?

If you use Verizon or another CDMA carrier it's unlikely that your smartphone is even technically capable of working in most other countries. If you have a GSM phone that has a SIM card, the easiest way to get data is usually to buy a pay-as-you-go SIM card with data from a carrier in whatever country you are in. Most US carriers have some sort of international plan but unless you are traveling all the time they are probably too expensive to be worth it.posted by burnmp3s at 7:00 AM on September 4, 2012

On a stand-alone GPS, the maps will be stored on the unit, often on memory card.

On a smartphone, the maps can either be downloaded as needed (for example Google Maps, which requires a data connection* to load new map data as you move around, or pan the map, or zoom in/out), or you can also get free or paid-for apps where the maps are downloaded onto the phone's memory so that it can function without needing a data connection - the same way as a stand-alone GPS unit.

*Although Google Maps actually has a new feature where you can download a portion of a map for later use without using any data.
What would I need to do to be able to have my smartphone's GPS working when I am abroad without data roaming?

You can buy various GPS phone apps that download the maps onto your phone for use without a data connection, for example on Android there's TomTom, Co-Pilot, or NavFree. Here are some iPhone examples.

when i say GPS - i mean one of the handheld ones you can walk around with or go hiking with. I don't mean a Garmin GPS unit for driving in your car.

The GPS units that are specifically for walking/hiking often have terrain maps (i.e. with contours, footpaths, etc) rather than the Google Map style roads-only maps.posted by EndsOfInvention at 7:01 AM on September 4, 2012

A handheld GPS usually is loaded with maps internally and can be used without an internet connection. Designed for outdoor activity, it's more rugged.

A smartphone GPS requires an internet connection to pull up map data.

Basically, if you are leaving town for the outdoors, your smartphone GPS is of little use. Also, your handheld GPS will work anywhere in the world.posted by Argyle at 7:03 AM on September 4, 2012

Just to balance things out, one advantage of a cellphone GPS is that (in my experience, at least) it has much better startup time - because the phone already knows roughly where you are through cell tower positions, the time to get a GPS location is measured in seconds, while for a standalone unit that you don't turn on until you need it, that can be minutes.posted by Holy Zarquon's Singing Fish at 7:08 AM on September 4, 2012

For instance, often I can't use the GPS on my smartphone without data turned on as well. Is this so the maps can be downloaded?

I can't speak for every phone but on my iPhone, yes, it's so maps can be downloaded; and there are offline maps apps that will let you use it for navigation without a data connection. I use just such an app with topo maps for hiking.

What would I need to do to be able to have my smartphone's GPS working when I am abroad without data roaming?

In Tokyo I used a different offline maps app from the app store that would let me select a map region and detail level and download maps [from the hotel's wifi] before I headed out.posted by ftm at 7:12 AM on September 4, 2012

As well as everything other folks have mentioned, the maps on your phone are likely to be more up to date. You will at least be getting the most recent data that the provider has, rather than whatever was on the device when it was sold.posted by emilyw at 7:13 AM on September 4, 2012

The other difference between standalone and cellphone GPS is antenna size. A standalone GPS with a good WAAS fix will be within 5m uncertainty of the actual location. An iPhone GPS may claim the 5m uncertainty, but is often more like 50m. When mapping for OpenStreetMap, I can use my iPhone for rough location, but if I really need to know where something is, I bring along my Garmin.

If your device is supported, you can get free OSM Maps for it. These will be much more up to date (in some places at least) than anything Google or Bing has.posted by scruss at 7:18 AM on September 4, 2012 [1 favorite]

Here is a practical example. Earlier this summer I took a trip to Sequoia and King's Canyon National Park. We had very spotty cell coverage at the southern entrance to the parks. So spotty that the phone was essentially useless and thus its mapping capability was useless. In the parks there was similarly no coverage and leaving the park to go to Fresno we saw almost no coverage until we got out of the mountains.

With that said, my handheld GPS unit that I purchased before my smartphone worked properly and reliably the entire time. The map and business data is going on 4 years old now so that can't be completely relied upon but in the grand scheme of things it works out just fine.posted by mmascolino at 7:42 AM on September 4, 2012 [1 favorite]

I spent a couple of weeks in London with no data plan recently and I used offline Google Maps on my Android smartphone. It worked great, except it used up the battery so fast. I had to be really careful. I assume that a standalone GPS is better at this kind of thing - I know my Garmin GPS training watch will last for a good ten hours.posted by mskyle at 7:46 AM on September 4, 2012

iPhone if it matters

It does in this case. The Google Navigate/Maps apps are considerably better than any standalone GPS makers' software, Garmin or Tomtom or whomever in my experience (I have had to use many for my day job). This is one thing Android phones do extraordinarily well.posted by bonehead at 8:01 AM on September 4, 2012

Nokia Maps can all be downloaded ahead of time for free for any country. I've used this on their Symbian devices without a data connection.

Frustratingly their Windows Phone based devices seem to require a data connection to use the Maps application fully, even though the maps data is local.posted by Gomez_in_the_South at 8:21 AM on September 4, 2012

To answer the question more directly: some, but not all smartphones will require a data connection for the maps to be loaded. The longer battery life would be one of the advantages of a standalone devices, as already mentioned.posted by Gomez_in_the_South at 8:25 AM on September 4, 2012

From a different perspective, it's interesting to note that a standalone GPS (either one for a car or a handheld one for hiking) is a "true" GPS and the one on your phone is almost definitely a assistedGPS (or A-GPS). A combination of antenna size (as scruss alludes to), power limitations, and a desire for cell phones to operate very fast, results in cell phones needing assistance from (or worse, requiring) cell phone towers to provide the GPS ephemeris and almanac that a "true" GPS would directly receive from the satellites to provide the "first fix" for positioning. I am not aware of any smartphone that uses a "true" GPS (ie, not A-GPS), but that does not mean they do not exist.

The advantages for smartphones are that they can much faster than a "true" GPS (due to receiving the ephemeris/almanac faster) and can conceivably lock to satellites in a worse signal environment than a "true" GPS (since the smartphone only needs to "hear" a local cell phone tower rather than a satellite to download the ephemeris/almanac).

The disadvantages for smartphones is that your privacy is compromised - just using the assisted GPS (even with downloaded maps) indicates to your provider that you are around a certain area. Conceivably, the provider could even roughly triangulate your position by monitoring the received signal strength from multiple cell phone towers that are within range of you. In addition, if the A-GPS is badly designed, it might be unable to download the GPS ephemeris/almanac without the cell tower assistance. As a result, you might not be able to use the A-GPS if you are in the middle of nowhere (ie, hiking). I've heard of this happening in cheaper smart phones, but only as an anecdote (ie, take it with a grain of salt).posted by saeculorum at 8:43 AM on September 4, 2012 [1 favorite]

Just for reference, I've got the TomTom app for iPhone. It's got maps for all of Western Europe, and if memory serves it's about 2GB in size, give or take. I don't actually have a car, but it comes in handy when driving with friends or family who either don't have GPS or have in-car GPS that lacks the various snazzy features available to the internet connected (live traffic updates, Google POIs, etc).

In my experience (with an iPhone 4S), it's pretty reliable. Every now and again, it'll freak out and think you're driving through a field/under the sea or something stupid, but this is pretty rare and only usually happens when I've got lousy/no reception, probably for the various reasons of A-GPS already mentioned. Another advantage is that smartphone navigation apps are on the whole significantly cheaper than a dedicated unit, so that along with the convenience of not having a whole separate unit are significant pluses in their favour. On top of that, you'll always have up-to-date maps, something which isn't the case with dedicated GPS units (at least not without a bit of effort).posted by jaffacakerhubarb at 9:18 AM on September 4, 2012

I have found the combination of an HTC Desire and Alpine Quest (£5.00) to be the equal of a £300+ GPS unit for UK OS maps.posted by Dr.Pill at 1:39 PM on September 4, 2012

There is not a hell of a lot of difference between the two. One of the main differences is that most smartphones will not allow or enable raw NMEA data to be viewed. NMEA data is the raw satellite data that can be used by most mapping applications and can be streamed from a standalone unit or viewed on a standalone unit (Garmin, Magellan, Trimble, etc.,). For GPS geeks, the ability is very important for post-processing. Raw NMEA data looks like this:

I use my GPSs mostly for driving, not hiking, but some of the same considerations might apply. I have a standalone Garmin GPS unit and two GPS apps on my Android phone - Google maps and an app called Copilot. For me, the standalone unit's main strength is that it requires no internet connection whatsoever. But its maps and POI (points of interest) lists never get updated, and it takes significantly longer to get a GPS lock - several minutes vs. a few seconds for the phone.

To me the phone's advantages are its fast GPS lock aided by cell tower positioning. Privacy issues notwithstanding, it's just so much dang faster than the standalone. It has updated maps and POIs, and a more responsive interface (maybe I just have a lousy standalone GPS, but its touch screen feels very sluggish compared to the phone).

The phone's main disadvantage is that it either requires an active data connection (Google navigation), or you need to pre-download some large maps to your phone. Apps like Copilot need the initial map download but can then work entirely offline, including re-routing, which I don't think Google does. Personally I far prefer the phone apps to the standalone GPS, but I guess it depends on your usage patterns, the particular GPS unit and GPS apps.posted by asynchronous at 8:33 PM on September 4, 2012

I've used both a handheld GPS unit and an android phone while walking in the hills. (And I had a paper map too: safety first, n'all that.)

This is in the UK, using the Grid system and OS Explorer Maps. Not sure how this works in other countries.

The handheld unit I had was one of the basic Garmin models, so it didn't have any maps on it, but it knew my location, and I'd pre-loaded my expected route on to it. It would show me the direction I was heading in, my current co-ordinates (and Grid ref), the line of my expected route, and where I'd already walked. Battery life is excellent, and it runs on three rechargable AAs. It's always been able to get a signal, but I've not been underground or anything exceptional with the GPS. I've dropped it on rocks (but not too far) a few times, and it's switched itself off. But it's remembered everything when I've switched it back on.

I would only use this in conjunction with a paper map (and actually the paper map is my primary means of navigation). The GPS lets me get a Grid ref and bearing, and double check with the programmed route. I've had to go off-route a few times, so it's been good to not have to stick to the programmed route.

The android phone comes with Google Maps, which needs pre-caching or data signal to receive. The maps aren't really great for walking in the hills. Especially true if there's no signal, which there often isn't. There's also an app that works with OS Maps in the UK, which gives great mapping. The only problem is that both mapping apps seem to drain the battery really quickly. The phone tends not to last for a 5 hour walk (not even a 3 hour walk with my particular phone).

The flipside to this is that Google maps is absolutely brilliant for navigating in a city/town: good signals and the detailed mapping of streets is really useful. Couple that with the fact that Google knows where most shops/restaurants are and it's pretty awesome.posted by SuckPoppet at 8:36 AM on September 5, 2012 [1 favorite]

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